CN110944372A

CN110944372A - Controlling MIMO layers for UE power saving

Info

Publication number: CN110944372A
Application number: CN201910869880.9A
Authority: CN
Inventors: 金唯哲; 孙海童; 曾威; 张大伟
Original assignee: Apple Inc
Current assignee: Apple Inc
Priority date: 2018-09-25
Filing date: 2019-09-16
Publication date: 2020-03-31
Anticipated expiration: 2039-09-16
Also published as: EP3629634A1; CN110944372B; US12010616B2; US20240284326A1; CN117354905A; US20200100178A1

Abstract

The present disclosure relates to controlling MIMO layers for UE power saving. The present disclosure relates to techniques for dynamically adjusting the number of active receiver chains of a wireless device. Based on communication parameters exchanged with the base station, the device may determine a maximum number of receiver chains required for data reception during one or more time periods. Such dynamic adjustment may enable power savings.

Description

Controlling MIMO layers for UE power saving

Priority requirement

Priority of U.S. provisional patent application serial No. 62/736,336 entitled "Controlling MIMO Layers for UEPower Saving" filed on 25/9/2018, which is incorporated herein by reference in its entirety as if fully and completely set forth herein.

Technical Field

The present patent application relates to wireless devices, and more particularly, to systems, methods, and apparatuses for reducing power consumption by opportunistically de-energizing one or more receiver chains.

Background

The use of wireless communication systems is growing rapidly. In addition, there are a number of different wireless communication technologies and standards. Some examples of wireless communication standards include GSM, UMTS (e.g., associated with WCDMA or TD-SCDMA air interfaces), LTE-advanced (LTE-A), 5G New Radio (NR), HSPA, 3GPP2 CDMA2000 (e.g., 1xRTT, 1xEV-DO, HRPD, eHRPD), IEEE 802.11(WLAN or Wi-Fi), IEEE802.16(WiMAX), Bluetooth, and so forth.

The mobile electronic device may take the form of a smartphone or tablet computer that the user typically carries. A wearable device (also referred to as an accessory device) is a newer form of mobile electronic device, one example being a smart watch. Typically, mobile electronic devices have relatively limited energy storage capabilities, such as battery capacity. In general, it is desirable to reduce the power requirements of communication devices, including both wearable devices and more traditional wireless devices such as smartphones. For example, powering a larger number of receiver chains for multi-tier communications may result in greater power usage than powering a smaller number of receiver chains. Accordingly, improvements in the art are desired.

Disclosure of Invention

Embodiments presented herein include, among other things, systems, methods, and apparatus for reducing power requirements of a wireless device by opportunistically de-energizing one or more receiver chains.

A wireless device may include multiple receiver chains that may be used to receive information using one or more wireless technologies. In some embodiments, multiple receiver chains may be configured for multiple-input, multiple-output (MIMO) communications. Each of the plurality of receiver chains may be configured to be independently powered down.

The wireless device may exchange communication parameters with the base station. The wireless device may dynamically determine the maximum number of MIMO layers based on communication parameters and possibly other factors such as one or more inactivity timers. The wireless device may adjust the number of active receiver chains based on the number of MIMO layers.

It is noted that the techniques described herein may be implemented in and/or used with a plurality of different types of devices, including but not limited to base stations, access points, cellular phones, portable media players, tablets, wearable devices, and various other computing devices.

This summary is intended to provide a brief overview of some of the subject matter described in this document. Thus, it should be understood that the above-described features are merely examples and should not be construed to narrow the scope or spirit of the subject matter described herein in any way. Other features, aspects, and advantages of the subject matter described herein will become apparent from the following detailed description, the accompanying drawings, and the claims.

Drawings

A better understanding of the present subject matter can be obtained when the following detailed description of the embodiments is considered in conjunction with the following drawings, in which:

fig. 1 illustrates an exemplary (and simplified) wireless communication system in accordance with some embodiments;

fig. 2 illustrates a Base Station (BS) in communication with a User Equipment (UE) device, in accordance with some embodiments;

fig. 3 illustrates an exemplary block diagram of a UE device according to some embodiments;

fig. 4 illustrates an exemplary block diagram of a BS according to some embodiments;

fig. 5 illustrates an exemplary block diagram of a receiver chain of a UE according to some embodiments;

fig. 6 is a flow diagram illustrating an exemplary method for controlling multiple receiver chains, according to some embodiments;

fig. 7 and 8 are graphs illustrating power consumption over time according to some embodiments;

fig. 9 and 10 are timing diagrams illustrating portions of bandwidth associated with inactivity timers, according to some embodiments; and is

Fig. 11 is a timing diagram illustrating dynamic adjustment of the number of layers according to some embodiments.

While the features described herein are susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the disclosure to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the subject matter as defined by the appended claims.

Detailed Description

Term(s) for

The following is a glossary of terms used in this disclosure:

memory medium-any of various types of non-transitory memory devices or storage devices. The term "storage medium" is intended to include mounting media such as CD-ROM, floppy disk, or tape devices; computer system memory or random access memory such as DRAM, DDR RAM, SRAM, EDO RAM, Rambus RAM, etc.; non-volatile memory such as flash memory, magnetic media, e.g., a hard disk drive or optical storage; registers or other similar types of memory elements, and the like. The memory medium may also include other types of non-transitory memory or combinations thereof. Further, the memory medium may be located in a first computer system executing the program, or may be located in a different second computer system connected to the first computer system through a network such as the internet. In the latter case, the second computer system may provide program instructions to the first computer for execution. The term "memory medium" may include two or more memory media that may reside at different locations in different computer systems, e.g., connected by a network. The memory medium may store program instructions (e.g., embodied as a computer program) that are executable by one or more processors.

Carrier mediumQuality of foodMemory media as described above, as well as physical transmission media such as buses, networks, and/or other physical transmission media that convey signals such as electrical, electromagnetic, or digital signals.

Programmable hardware element-including various hardware devices including a plurality of programmable functional blocks connected via programmable interconnects. Examples include FPGAs (field programmable gate arrays), PLDs (programmable logic devices), FPOAs (field programmable object arrays), and CPLDs (complex PLDs). Programmable function blocks can range from fine grained (combinatorial logic units or look-up tables) to coarse grained (arithmetic logic units or processor cores). The programmable hardware elements may also be referred to as "configurable logic components".

Computer systemAny of various types of computing systems or processing systems, including Personal Computer Systems (PCs), mainframe computer systems, workstations, network appliances, internet appliances, Personal Digital Assistants (PDAs), television systems, grid computing systems, or other devices or combinations of devices. In general, the term "computer system" may be broadly defined to encompass any device (or combination of devices) having at least one processor that executes instructions from a memory medium.

User Equipment (UE) (or "UE device")Any of various types of computer system devices that are mobile or portable and perform wireless communications. Examples of UE devices include mobile phones or smart phones (e.g., iphones)^TMBased on Android^TMTelephone), portable gaming devices (e.g., Nintendo DS)^TM、PlayStation Portable^TM、Gameboy Advance^TM、iPhone^TM) A laptop, a wearable device (e.g., a smart watch, smart glasses), a PDA, a portable internet appliance, a music player, a data storage device, or other handheld device, etc. In general, the term "UE" or "UE device" may be broadly defined to encompass any electronic, computing, and/or telecommunications device (or combination of devices) that is easily communicated by a user and capable of wireless communication.

Wireless deviceAny of various types of computer system devices performing wireless communication. The wireless device may be portable (or mobile) or may be fixed or fixed in some location. A UE is an example of a wireless device.

Base stationThe term "base station" has its full scope in its ordinary meaning and includes at least a wireless communication station installed at a fixed location and used for communicating as part of a wireless telephone system or a radio system.

Link budget limitation-full width including its ordinary meaning and including at least the characteristics of a wireless device (UE) exhibiting limited communication capabilities or limited power with respect to devices that are not link budget limited devices or with respect to devices that have developed Radio Access Technology (RAT) standards. A link budget limited UE may experience relatively limited reception and/or transmission capabilities, which may be due to one or more factors such as device design, device size, battery size, antenna size or design, transmission power, reception power, current transmission medium conditions, and/or other factors. Such devices may be referred to herein as "link budget limited" (or "link budget constrained") devices. A device may be inherently link budget limited due to hardware limitations of the device, such as its size, battery power, and/or transmit/receive power. For example, a smart watch communicating with a base station over NR, LTE or LTE-a may be inherently link budget limited due to, for example, a reduction in its transmit/receive power and/or a reduction in antennas relative to a smart phone. Wearable devices such as smart watches are generally link budget limited devices. Alternatively, the device may not be inherently link budget limited, e.g., may have sufficient size, battery power, and/or transmit/receive power for normal communications over LTE or LTE-a, but may be temporarily link budget limited due to current communication conditions, e.g., a smartphone is at a cell edge, etc. It is noted that the term "link budget limited" includes or encompasses power limitations, and thus a link limited device may be considered a link budget limited device.

Processing element (orProcessor)-refers to various elements or combinations of elements. The processing elements include, for example, circuitry such as an ASIC (application specific integrated circuit), portions or circuits of various processor cores, an entire processor core, various processors, a programmable hardware device such as a Field Programmable Gate Array (FPGA), and/or a larger portion of a system including multiple processors.

Channel with a plurality of channels-a medium for transferring information from a sender (transmitter) to a receiver. It should be noted that the term "channel" as used herein may be considered to be used in a manner that conforms to a standard for the type of device to which the term is being referred, since the characteristics of the term "channel" may differ from one wireless protocol to another. In some standards, the channel width may be variable (e.g., depending on device capabilities, band conditions, etc.). For example, LTE may support a scalable channel bandwidth of 1.4MHz to 20 MHz. In contrast, a WLAN channel may be 22MHz wide, while a bluetooth channel may be 1MHz wide. Other protocols and standards may include different definitions for channels. Further, some standards may define and use multiple types of channels, e.g., different channels for uplink or downlink and/or different channels for different purposes such as data, control information, and so on.

Frequency bandThe term "frequency band" has its full scope in its ordinary meaning and includes at least a segment of the spectrum (e.g., the radio frequency spectrum) in which channels are used or set aside for the same purpose.

AutomaticAn action or operation performed by a computer system (e.g., software executed by a computer system) or device (e.g., circuit, programmable hardware element, ASIC, etc.) without user input directly specifying or performing the action or operation. Thus, the term "automatically" is in contrast to a user manually performing or specifying an operation, wherein the user provides input to directly perform the operation. An automatic process may be initiated by input provided by a user, but subsequent actions performed "automatically" are not specified by the user, i.e., are not performed "manually," where the user specifies each action to be performed. For example, the user specifies information by selecting each field and providing input (e.g., byBy typing information, selecting check boxes, radio selection, etc.) to fill out an electronic form is to manually fill out the form, even though the computer system must update the form in response to user action. The form may be automatically filled in by a computer system, wherein the computer system (e.g., software executing on the computer system) analyzes the fields of the form and fills in the form without any user entering answers specifying the fields. As indicated above, the user may invoke automatic filling of the form, but not participate in the actual filling of the form (e.g., the user does not manually specify answers for the fields but rather they are automatically completed). This specification provides various examples of operations that are automatically performed in response to actions that have been taken by a user.

FIG. 1 and FIG. 2-communication system

Fig. 1 illustrates an exemplary (and simplified) wireless communication system according to some embodiments. It is noted that the system of fig. 1 is only one example of possible systems, and embodiments may be implemented in any of a variety of systems, as desired.

As shown, the exemplary wireless communication system includes a base station 102A that communicates with one or more user devices 106A, 106B, etc. to a user device 106N over a transmission medium. Each of the user equipments may be referred to herein as a "user equipment" (UE). Thus, the user equipment 106 is referred to as a UE or UE device.

The base station 102A may be a Base Transceiver Station (BTS) or a cell site and may include hardware to enable wireless communication with the UEs 106A-106N. The base station 102A may also be equipped to communicate with a network 100 (e.g., a core network of a cellular service provider, a telecommunications network such as a Public Switched Telephone Network (PSTN) and/or the internet, among various possibilities). Thus, the base station 102A may facilitate communication between user equipment and/or between user equipment and the network 100.

The communication area (or coverage area) of a base station may be referred to as a "cell". Base station 102A and UE106 may be configured to communicate via a transmission medium using any of a variety of Radio Access Technologies (RATs), also referred to as wireless communication technologies or telecommunication standards, such as GSM, UMTS (WCDMA, TD-SCDMA), LTE-advanced (LTE-a), 5G NR, HSPA 3GPP2 CDMA2000 (e.g., 1xRTT, 1xEV-DO, HRPD, eHRPD), Wi-Fi, WiMAX, and so forth.

Base station 102A and other similar base stations operating according to the same or different cellular communication standards, such as base station 102b.

Thus, although base station 102A may serve as a "serving cell" for UEs 106A-N as shown in fig. 1, each UE106 may also be capable of receiving signals (and possibly be within its communication range) from one or more other cells (which may be provided by base stations 102B-N and/or any other base stations), which may be referred to as "neighboring cells. Such cells may also be capable of facilitating communication between user devices and/or between user devices and network 100 according to the same wireless communication technology as base station 102A and/or any of a variety of other possible wireless communication technologies. Such cells may include "macro" cells, "micro" cells, "pico" cells, and/or cells providing any of a variety of other granularities of service area size. For example, the base stations 102A-B shown in fig. 1 may be macro cells, while the base station 102N may be a micro cell. Other configurations are also possible.

Note that the UE106 may be capable of communicating using multiple wireless communication standards. For example, in addition to at least one cellular communication protocol (e.g., NR, GSM, UMTS (WCDMA, TD-SCDMA), LTE-A, HSPA, 3GPP2 CDMA2000 (e.g., 1xRTT, 1xEV-DO, HRPD, eHRPD), etc.), the UE106 may be configured to communicate using wireless networking (e.g., Wi-Fi) and/or peer-to-peer wireless communication protocols (e.g., BT, Wi-Fi pairs, etc.). If desired, the UE106 may also or alternatively be configured to communicate using one or more global navigation satellite systems (GNSS, such as GPS or GLONASS), one or more mobile television broadcast standards (e.g., ATSC-M/H or DVB-H), and/or any other wireless communication protocol. Other combinations of wireless communication standards, including more than two wireless communication standards, are also possible.

Fig. 2 illustrates a user equipment 106 (e.g., one of devices 106A-106N) in communication with a base station 102 (e.g., one of base stations 102A-102N), according to some embodiments. The UE106 may be a device with cellular communication capabilities, such as a mobile phone, a handheld device, a wearable device, a computer or a tablet, or virtually any type of wireless device.

The UE106 may include a processor configured to execute program instructions stored in a memory. The UE106 may perform any of the method embodiments described herein by executing such stored instructions. Alternatively or additionally, the UE106 may include programmable hardware elements, such as an FPGA (field programmable gate array) configured to perform any of the method embodiments described herein or any portion of any of the method embodiments described herein.

The UE106 may include one or more antennas and one or more radios for communicating using one or more wireless communication protocols or technologies. In one embodiment, the UE106 may be configured to communicate using CDMA2000(1xRTT/1xEV-DO/HRPD/eHRPD) or LTE using a single shared radio and/or one or more of GSM or LTE using a single shared radio. The shared radio may be coupled to a single antenna or may be coupled to multiple antennas (e.g., for MIMO) for performing wireless communications. In general, the radio components may include any combination of baseband processors, analog RF signal processing circuits (e.g., including filters, mixers, oscillators, amplifiers, etc.), or digital processing circuits (e.g., for digital modulation and other digital processing). Similarly, the radio may implement one or more receive chains and transmit chains using the aforementioned hardware. For example, the UE106 may share one or more portions of a receive chain and/or a transmit chain among multiple wireless communication technologies, such as those discussed above. Additionally, in some embodiments, the UE106 may include multiple receiver chains, e.g., for MIMO communications.

In some embodiments, the UE106 may include separate (and possibly multiple) transmit chains and/or receive chains (e.g., including separate RF and/or digital radios) for each wireless communication protocol with which it is configured to communicate. As another possibility, the UE106 may include one or more radios shared between multiple wireless communication protocols, as well as one or more radios used exclusively by a single wireless communication protocol. For example, the UE106 may include a shared radio for communicating using any of NR, LTE, and/or 1xRTT (or UMTS or GSM), as well as a separate radio for communicating using each of Wi-Fi and bluetooth. Other configurations are also possible.

FIG. 3-exemplary block diagram of a UE device

Fig. 3 shows one possible block diagram of a UE device, such as UE device 106. As shown, the UE device 106 may include a System On Chip (SOC)300, which may include portions for various purposes. For example, as shown, SOC 300 may include one or more processors 302 that may execute program instructions, and display circuitry 304 that may perform graphics processing and provide display signals to display 360. The one or more processors 302 may also be coupled to a Memory Management Unit (MMU)340, which Memory Management Unit (MMU)340 may be configured to receive addresses from the one or more processors 302 and translate the addresses to those addresses of locations in memory (e.g., memory 306, Read Only Memory (ROM)350, flash memory 310). MMU 340 may be configured to perform memory protections and page table translations or settings. In some embodiments, MMU 340 may be included as part of one or more processors 302.

The UE device 106 may also include other circuitry or devices, such as display circuitry 304, a receiver chain 330, a dock/connector I/F320, and/or a display 340.

In the illustrated embodiment, the ROM 350 may include a boot loader that is executable by the one or more processors 302 during startup or initialization. As also shown, the SOC 300 may be coupled to various other circuits of the accessory device 107. For example, the UE device 106 may include various types of memory, a connector interface 320 (e.g., for coupling to a computer system), a display 360, and wireless communication circuitry/one or more receiver chains 330 (e.g., for communication utilizing cellular, Wi-Fi, bluetooth, NFC, GPS, etc.). In some implementations, one or more of the wireless communication circuitry/one or more receiver chains 330 may perform both sending (e.g., transmission) and receiving functions.

The UE device 106 may include at least one receiver chain 330 (e.g., receiver chain 330a as shown), and in some embodiments, a plurality of receiver chains (e.g., including any number of receiver chains 330b-330 n) for performing wireless communications with base stations and/or other devices. The UE device 106 may communicate with base stations and other devices implementing different wireless technologies in some embodiments. In particular, the UE device 106 may employ multiple receiver chains 330a-330n for MIMO communications, e.g., using cellular communications. In various possibilities, each receiver (Rx) chain 330a-330n may include baseband circuitry 332 and RF processing circuitry 334, as well as an antenna 338. In some embodiments, some components may be shared between multiple receiver chains. For example, the baseband circuitry may be implemented as a shared processor that processes multiple Rx-chain signals simultaneously. In some embodiments, not all of the illustrated components of the receiver chains 330a-330n may be included. The individual receiver chains may be independently powered, e.g., such that one subset of the receiver chains 330 may be powered or active while another subset may be powered-off or inactive. It is noted that the term power-down as used herein may include a variety of possible states, including a low-power state, a fully powered-down state, a sleep state, and the like. Additionally, the receiver chain may be configured such that individual elements/components of the receiver chain may be independently powered or unpowered. For example, in some embodiments, one element (e.g., baseband processor 332) may be powered up/down more quickly relative to other components of the receiver chain; for example, the baseband processor 332 may have a "power down time" or "cycle time" that is shorter than the other elements. Thus, in some cases, there may be an opportunity to conserve power by temporarily de-energizing one or more elements without de-energizing the rest of the chain (e.g., because the amount of time to de-energize and re-energize the remaining components may exceed the amount of time before these components may be needed). In other words, a particular element may be selected to power down based on a comparison of a power down time and a Transmission Time Interval (TTI) associated with an active communication session. In some embodiments, a single receiver chain may include multiple antennas.

For example, the UE device 106 may perform wireless communication using one or more antennas 338. As described above, a UE may be configured in some embodiments to wirelessly communicate using multiple wireless communication standards or Radio Access Technologies (RATs).

As described herein, the one or more receiver chains 330 may include hardware components and software components for implementing embodiments of the present disclosure. The one or more receiver chains 330 of the UE device 106 may be configured to implement a portion or all of the methods described herein, for example, by a processor executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium), a processor configured as an FPGA (field programmable gate array), and/or using special-purpose hardware components that may include an ASIC (application specific integrated circuit).

The receiver chain 330 may also include elements not shown, such as Wi-Fi logic and Bluetooth logic. The Wi-Fi logic may enable the UE device 106 to perform Wi-Fi communications over the 802.11 network. The bluetooth logic may enable the UE device 106 to perform bluetooth communications.

As described further herein subsequently, the UE106 may include hardware and/or software components for implementing features for controlling the plurality of active receiver chains 330, such as those features described herein with reference to fig. 6. The processor 302 of the UE device 106 may be configured to implement some or all of the methods described herein, for example, by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium). In other embodiments, the processor 302 may be configured as a programmable hardware element such as an FPGA (field programmable gate array), or as an ASIC (application specific integrated circuit). Alternatively (or in addition), the processor 302 of the UE device 106, in conjunction with one or more of the other components, may be configured to implement some or all of the features described herein, such as the features specifically described herein with reference to fig. 6.

FIG. 4-exemplary block diagram of a base station

Fig. 4 illustrates an example block diagram of a base station 102 in accordance with some embodiments. It is noted that the base station of fig. 4 is only one example of possible base stations. As shown, base station 102 may include one or more processors 404 that may execute program instructions for base station 102. The one or more processors 404 may also be coupled to a Memory Management Unit (MMU)440, which may be configured to receive addresses from the one or more processors 404 and translate the addresses to locations in memory (e.g., memory 460 and Read Only Memory (ROM)450), or to other circuits or devices.

The base station 102 may include at least one network port 470. The network port 470 may be configured to couple to a telephone network and provide a plurality of devices, such as the UE device 106, with access to the telephone network as described above in fig. 1 and 2.

The network port 470 (or additional network ports) may be further configured or alternatively configured to couple to a cellular network, such as a core network of a cellular service provider. The core network may provide mobility-related services and/or other services to multiple devices, such as UE device 106. In some cases, the network port 470 may be coupled to a telephone network via a core network, and/or the core network may provide the telephone network (e.g., in other UE devices served by a cellular service provider).

Base station 102 may include at least one antenna 434 and possibly multiple antennas. The one or more antennas 434 may be configured to operate as wireless transceivers and may be further configured to communicate with the UE device 106 via the radio 430. Antenna 434 communicates with radio 430 via communication link 432. Communication chain 432 may be a receive chain, a transmit chain, or both. Radio 430 may be configured to communicate via various wireless telecommunication standards including, but not limited to, NR, LTE-a, UMTS, CDMA2000, Wi-Fi, and the like.

BS 102 may be configured to wirelessly communicate using a plurality of wireless communication standards. In some cases, base station 102 may include multiple radios that may enable base station 102 to communicate in accordance with multiple wireless communication technologies. For example, as one possibility, base station 102 may include an NR radio to perform communications according to NR and a Wi-Fi radio to perform communications according to Wi-Fi. In such cases, base station 102 may be capable of operating as both an LTE base station and a Wi-Fi access point. As another possibility, the base station 102 may include a multi-mode radio capable of performing communications in accordance with any of a number of wireless communication technologies (e.g., NR, LTE, and Wi-Fi). BS 102 may be referred to as a gNB.

BS 102 may be configured to communicate in accordance with MIMO techniques. For example, BS 102 may use multiple antennas 434 to communicate with UEs 106 using one or more of its transmit and/or receiver chains 330a-330 nnn. For example, one or more transmit chains and/or receiver chains may be included in communication chain 432. Technical standards may describe various modes for communication between these devices, e.g., the LTE standard may describe various Transmission Modes (TM) that may specify different transmission schemes for Physical Downlink Shared Channel (PDSCH) messages. For example, TM1 may utilize only a single antenna, while other (e.g., higher numbered) modes may utilize additional antennas. One or more Physical Downlink Control Channel (PDCCH) messages may include control information. The control information may include an assigned level (e.g., a level identifier or RI) and a Modulation and Coding Scheme (MCS). The nature of the control information may vary between different transmission modes. For example, according to TM3 and TM4, a Precoding Matrix Indicator (PMI) may be included, but according to TM9, a PMI may not be included.

BS 102 may include hardware and software components for implementing or supporting the specific implementation of features described herein. The processor 404 of the base station 102 may be configured to implement a portion or all of the methods described herein, for example, by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium). Alternatively, the processor 404 may be configured as a programmable hardware element such as an FPGA (field programmable gate array), or as an ASIC (application specific integrated circuit), or a combination thereof. Alternatively (or in addition), processor 404 of BS 102, in conjunction with one or more of the

other components

430, 432, 434, 440, 450, 460, 470, may be configured to implement some or all of the features described herein.

FIG. 5-exemplary block diagram of a receiver chain of a wireless device

Fig. 5 is a block diagram illustrating an exemplary set of receiver chains (e.g., receiver chain 330) for a wireless device, such as one of UEs 106 shown in fig. 1-3. It should be noted that the exemplary features illustrated in fig. 5 and described with respect to fig. 5 are not intended to limit the present disclosure as a whole: many variations and alternatives to the details provided below with respect to fig. 5 are possible and should be considered within the scope of the present disclosure.

As shown, the UE106 (e.g., receiver chain 330) may include an RF portion 334 and a baseband (BB) portion 332. The RF section 334 may be coupled to one or more antennas 338. In some embodiments, the UE may include multiple RF portions 334 and/or multiple BB portions 332. Either or both of RF334 and BB332 may include elements of one or more receiver (Rx) chains 330. Further, either or both of RF334 and BB332 may comprise elements of one or more transmitter chains. The receiver and transmitter (Tx) chains may share some or all of the elements, or may be completely independent (e.g., may not share any elements). In the illustrated embodiment, two Rx chains are shown, but it should be understood that any number of Rx chains is possible.

The receiver chain may include one antenna and various elements within RF334 and BB 332. As shown, the receiver chain may include the following elements in RF 334: band Pass Filters (BPF), Low Noise Amplifiers (LNA), mixers, Low Pass Filters (LPF) and Automatic Gain Control (AGC). According to some embodiments, the RF component of the receiver chain may be a single Integrated Circuit (IC). The RF IC may include multiple parallel chains of signal processing blocks (e.g., the illustrated elements and/or additional or alternative elements). Each chain may correspond to a physical antenna.

The characteristics of the receiver chain included in BB332 may vary in different implementations. The receiver chain may also include an analog-to-digital converter (ADC), which may be included in BB 332. It should be noted that according to some embodiments, the ADC may be included in the RF334 instead of the BB 332. BB332 may include one or more elements (or perform logic functions corresponding to such elements) that may be shared among any number of Rx chains. For example, as shown, BB332 may include equalization and channel estimation functions, which may be performed for any corresponding signal (e.g., Rx chain) number using shared or dedicated processing and/or memory. Other functions of BB332 may include signal buffering; BB332 may use shared or dedicated processing and/or memory to perform buffering for any number of signals/number of Rx chains. BB332 may comprise multiple paths of a signal processing chain (e.g., Rx chain). Note that in some implementations of BB332, the Rx chain may be a logical concept. In other words, BB332 may be a shared processing circuit that may be configured to process multiple Rx-chain signals simultaneously.

In some embodiments, one antenna may correspond to one Rx chain (e.g., one IC) in RF 334. The Rx chain may further include an ADC, which may be included in BB332 or RF 334. The Rx chain may include any number of ICs that perform RF and/or BB functions.

In some embodiments, multiple antennas may correspond to one Rx chain or multiple Rx chains may correspond to a single antenna. In some embodiments, an antenna switch block may be included to switch or modify the connection between one or more antennas and one or more Rx chains. In some embodiments, some or all of the components of RF334 may be shared by one or more Rx chains.

The UE106 may be configured to independently power on or power off one or more receiver chains. Among various possibilities, de-energizing the receiver chain may include turning off the LNA, mixer, BPF, and LPF. De-powering the receiver chain may further include reducing the use of ADCs, signal buffering, channel estimation, and equalization, for example, in the shared BB processing circuitry. Furthermore, reducing the number of active receiver chains may reduce the use of memory, processors, or other shared resources, which may further reduce power consumption. Such reduced use may reduce power consumption of the shared circuitry.

FIG. 6-flow chart for receiver chain de-energizing

In some embodiments, a wireless device (e.g., UE 106) may have a limited power source (e.g., a battery). In addition, extending battery life may be a valuable feature for users of the device. Powering each receiver chain may require a significant amount of power requirements. Thus, de-energizing as many receiver chains as possible when those chains are not in use or are under-used can extend the battery life of the device.

According to some specifications, such as NR, the number of antennas and/or receiver chains used to receive data may vary over time. For example, a UE device with multiple-input multiple-output (MIMO) communication capability may use up to eight antennas and/or receiver chains, among various possibilities. BS 102 may transmit data to the UE using a variety of techniques; these techniques may require different active (e.g., powered) receiver chain numbers for a UE (e.g., UE 106) to successfully receive and decode data. For example, in MIMO communications, the transmission from BS 102 may include various MIMO layer numbers. The UE may receive the MIMO layers for each transmission using one receiver chain (and corresponding antenna). In current NR, according to some embodiments, for single user MIMO (SU-MIMO), the network may support up to 8 MIMO layers. It should be noted that the techniques described herein may be applied to other number of layers and other types of transmission, such as MU-MIMO.

During Radio Resource Control (RRC) configuration, according to some embodiments, the maximum number of MIMO layers to support may be determined based on a number of codewords (e.g., and/or a related notion of transport blocks) supported by the UE. For example, the number of codewords may be indicated by a parameter named maxnrof codewordsschedule bydci. If maxnrofcodewordsscheduled bydci is 1, the network may send up to 4 layers for a single codeword during the Transmission Time Interval (TTI) for which the parameters apply. If maxnrofcodewordsscheduled bydci is 2, the network may send up to 8 layers for two codewords during a TTI. In other words, the network may send layers 1-4 for codeword 1 and layers 5-8 for codeword 2 (e.g., may transmit up to the first 4 layers for the first codeword and up to the second 4 layers for the second codeword). For example, if 5 layers are transmitted, layers 1-4 may be used for codeword 1 and layer 5 may be used for codeword 2. In some embodiments, the maxnrof codewordsscheduled bydci parameter and corresponding maximum number of MIMO layers may remain valid for the duration of the RRC connection. Therefore, this maximum number of layers may be referred to as a static maximum.

For a UE in RRC connected mode, the actual MIMO layer number (relative to maximum) may be dynamically indicated and adjusted by Downlink Control Information (DCI) transmitted during a Physical Downlink Control Channel (PDCCH) of a Physical Downlink Shared Channel (PDSCH). For example, an "antenna port field" value in DCI may indicate how many MIMO layers to transmit for the corresponding PDSCH. If maxnrof codewordsschedule bydci is 1, the network/BS may indicate one of 1, 2, 3, or 4 layers to transmit a single codeword. If maxnrof codewordsschedule bydci is 2, the network may instruct one of 5, 6, 7, or 8 layers to transmit two codewords. These number of layers and code words are merely exemplary and other numbers may be used.

Note that as the number of MIMO layers to support increases, the UE power consumption may increase (e.g., because each active Rx chain may use power). The UE (e.g., modem) may need time to decode the DCI. For example, DCI decoding may end around a 5 th-9 th Orthogonal Frequency Division Multiplexing (OFDM) symbol in a slot. Until DCI decoding is complete, the UE may not know how many MIMO layers are transmitted for the potential PDSCH in the slot. Thus, the UE may open multiple receiver chains to process received signal samples corresponding to the maximum number of layers it supports (e.g., via maxnrof codewordsscheduled bydci according to the RRC configuration), rather than based on the actual number of MIMO layers being transmitted. Thus, the UE may consume a significant amount of power to process signal samples that may not actually be used for the UE. For example, when only two layers with a maximum number of layers equal to 4 (e.g., 1 codeword) are scheduled, the UE may buffer all 4 layer streams until the UE completes DCI decoding (to determine the actual number of layers scheduled). Thus, shutting down any unneeded receiver components or circuits as early as possible during the time slot may have significant power saving benefits.

Figure 6 illustrates a method for controlling the number of MIMO layers and thus selectively powering up and powering down a receiver chain, according to some embodiments. In various embodiments, some of the method elements shown may be performed concurrently, in a different order than shown, may be replaced by other method elements, or may be omitted. Additional method elements may also be performed as desired. Aspects of the method of fig. 6 may be implemented by a wireless device, such as the UE106 and/or BS 102 shown in fig. 1-3 and described with respect to the preceding figures, or more generally, in other devices, as desired, in conjunction with any of the computer systems or devices shown in the figures. For example, one or more processors of UE106 and/or BS 102 (e.g., such as processor 302, one or more processors included in receiver chain 330, processor 404, etc.) may cause such devices to perform any or all aspects of the method of fig. 6, in accordance with some embodiments. It is noted that while at least some elements of the method of fig. 6 are described using a manner that involves using communication techniques and/or features associated with 3GPP specification documents, such description is not intended to limit the disclosure, and aspects of the method of fig. 6 may be used in any suitable wireless communication system, as desired. For example, although aspects of the method of fig. 6 are described in relation to MIMO communication in NR, it should be noted that the method is applicable to other types of communication and wireless networks. Furthermore, although aspects of the method of fig. 6 are described in relation to downlink transmissions, it should be noted that the method is also applicable to uplink transmissions. As shown, the method may operate as follows.

According to some embodiments, a UE (e.g., UE 106) may establish communication with a base station (e.g., BS 102) and exchange one or more communication parameters with a BS (602). A BS may provide one or more cells of a (e.g., cellular) wireless network, and a UE may communicate with the base station using NR and/or other radio access technologies. In some embodiments, the BS may provide a WLAN network, for example, according to 802.11.

The UE and the BS may be configured to communicate using MIMO. In various possibilities, the one or more communication parameters may be used by the UE and/or the BS to determine the number of MIMO layers available for communication during one or more time periods. The UE may exchange communication parameters (and possibly other data) with the BS using any number of transmitters and/or receiver chains. For example, the UE and the BS may exchange application and/or control data in the uplink and/or downlink directions.

The UE and the BS may perform configuration, such as RRC configuration. For example, the UE may indicate (e.g., to the BS) the number of codewords it supports and/or the BS may indicate (e.g., to the UE) the maximum number of MIMO layers. Such an indication may be conveyed in any manner, such as by sending a corresponding message between the UE and the BS. The BS may explicitly indicate the first maximum MIMO layer number based on the codeword number (e.g., via maxnrof codewordsscheduled bydci).

In some embodiments, the BS may determine and indicate (or third, etc.) the maximum MIMO layer number or adjust the maximum value based on additional information. Such a second (and possibly subsequent) or adjusted maximum MIMO layer number may be used to dynamically limit/adjust the effective maximum MIMO layer number to more closely match the MIMO layer number that the BS may transmit to the UE in the upcoming time period/slot. Such adjustments to the maximum value may be determined based on various additional factors (e.g., channel conditions, preferences of the UE, etc.) and may be explicitly or implicitly indicated in various manners as described below. The adjusted/second and last maximum MIMO layer numbers may be less than or equal to the first maximum layer number. For example, if the first maximum is 8 layers (e.g., because two codewords are enabled), the BS may determine a dynamic adjustment to the maximum to adjust the maximum to 6 layers in response to channel conditions. The BS may further determine to adjust the maximum value back to layer 8 if the channel conditions improve. As an alternative embodiment, if the first maximum is 8 layers (e.g., because two codewords are enabled), the BS may set a conditional maximum of 4 layers, e.g., based on inactivity timer usage, e.g., during CDRX of duration). When one or more conditions are met (e.g., expiration of an inactivity timer), the BS may instruct the UE to use such a conditional maximum. In various possibilities, any such dynamic adjustment or conditional maximum may be referred to as an adjusted maximum, a configured maximum or second maximum, and/or may be referred to as adjusting a (e.g., first) maximum.

In some embodiments, the BS may configure the UE to use one or more bandwidth parts (BWPs) via one or more communication parameters. The bandwidth portion may be a contiguous region of frequency/spectrum where the UE may monitor transmissions from the BS. The BS may configure the UE to use one or more BWPs simultaneously. The BS may dynamically change the allocation of BWMs to UEs, e.g., via RRC signaling, via one or more Media Access Control (MAC) Control Elements (CEs), or via Downlink Control Information (DCI). The BWP allocation may continue until it is reconfigured or may remain active for a preconfigured amount of time.

In some embodiments, a particular BWP may be defined to use a particular maximum MIMO layer number. E.g. BWP_kMay include a maximum number of MIMO layers (e.g., N) to support configuration over the BWP_{max_L_k}). For example, for 1 codeword, N_{max_L_k}May be 1-4. For 2 code words, N_{max_L_k}May be 1 to 8. Alternatively, for a2 codeword, N is N according to some embodiments_{max_L_k}May be limited to 5-8. Other values are possible. The actual number of layers to be transmitted may be BWP compliant_kN in (1)_{max_L_k}And (4) limiting. This may allow the UE to turn on only N_{max_L_k}Receiver chain to be in BWP_kIn receiving at most N_{max_L_k}Layers or receiver chains are de-energized so that only N is affected_{max_L_k}The receiver chain is powered. In other words, the UE may be able to determine how many receiver chains to use based on the assigned BWP. Thus, whenever a UE is assigned to BWP_kThe UE can use N_{max_L_k}. Such allocation may be valid for any number of slots. In other words, N_{max_L_k}May be allocated to BWP_kThe conditional maximum of the UE.

Some exemplary BWP configurations are listed below. It is noted that these configurations are merely exemplary, and that other configurations may be used.

The first BWP, BWP1 may be of N_{max_L_k}Default or initial (narrow) BWP of 1. When the BWP inactivity timer expires (e.g., no traffic arrives for the duration of the inactivity timer), the UE may use and/or switch to this default BWP. In this case, the UE mayThe control signal is monitored primarily or solely. To save power, in the illustrated embodiment, the UE may operate with a small number of receiver chains, e.g., 1 receiver chain.

BWP2 may be a medium sized BWP, where N is_{max_L_k}2. This BWP may be used when the traffic is moderate, e.g. for VoLTE or web browsing.

BWP3 may be of N_{max_L_k}A large dimension BWP of 2. The BWP may be used when there are only a few users in a cell and the network may allocate sufficient resources to the UE under low signal-to-noise ratio (SNR) conditions. In other words, the BWP may be used near the cell edge, where more energy per layer may be available for reception.

BWP4 may be of N_{max_L_k}A large dimension BWP of 6. This BWP may be used when there is a large amount of traffic arriving (e.g., FTP or video streaming for the UE under high SNR conditions). In other words, the BWP may be used in high SNR regions (e.g., near the center of the cell), where more layers may provide higher throughput.

In some embodiments, the one or more communication parameters may include a parameter for a maximum number of layers to be received during connected mode discontinuous reception (CDRX) of a duration. Such a parameter may be referred to as N_{CDRX_L}. Thus, N_{CDRX_L}May be a conditional maximum for a UE operating in CDRX for duration. In other words, the maximum number of layers may be limited to N when operating in CDRX mode in BWP_{CDRX_L}. In some embodiments, may be based on N_{CDRX_L}Lower value of or maximum number of layers of current BWP of the UE, e.g. N_{max_L_k}To determine the maximum number of layers. In other words, the number of layers may be defined by: min (N)_{CDRX_L}，N_{max_L_k}) It is given. In other embodiments, N may be based_{CDRX_L}Or the number of layers associated with the number of supported codewords to determine the maximum number of layers (e.g., 4 for 1 codeword and 8 for 2 codewords). In other words, the largest layer may be formed by: min (N)_{CDRX_L}4 or 8-depending on the number of codewords). N is a radical of_{CDRX_L}May be configured by RRC or MAC CE.

In some embodiments, the communication parameters may include a dynamic indication of the maximum number of MIMO layers. Such dynamic indication may be more flexible than RRC signaling (e.g., it may be limited to indicating a maximum of 4 layers for 1 codeword or a maximum of 8 layers for 2 codewords, as described above). Such dynamic indication may be implemented, for example, through MAC CE signaling, among various possibilities. Thus, the MIMO layer number may be changed without changing BWP. Dynamic signaling may allow selection of any MIMO layer number as the maximum value. For example, if 1 codeword is enabled, layers 1-4 may be indicated; if 2 codewords are enabled, layers 1-8 may be indicated. The number of layers may vary with channel conditions (e.g., based on channel rank). The indicated number of layers may remain active for a fixed period of time until a certain condition is met or until changed. In other words, if a MAC CE is received indicating a maximum number of layers, the UE may use the maximum number for future slots until an indication of a changed number is received or other conditions are met.

In some embodiments, the UE may indicate one or more preferred maximum number of layers for the BS. The preferred number of layers may be specific to BWP. The UE may indicate a BWP-specific preference number for any BWP number. In some embodiments, the UE may indicate a preferred number of layers by indicating a preferred BWP, e.g., it may be associated with multiple layers. Multiple layers for CDRX operation may be indicated. These indications may remain valid for a fixed period of time until a certain condition is met or until changed. The indication may be sent via a mac ce or RRC message. For example, the UE may transmit the indication as UEAssistanceInformation. In some cases, the BS (e.g., network) may not comply with the UE indicated tier number preference.

The UE may select the preferred maximum number of layers to indicate to the BS based on any of various considerations. For example, the UE may consider any or all of the following: measurements of channel conditions assumed by the UE, measurements of channel conditions assumed by the BS or other device, rank, movement of the UE, expected traffic of the UE, status of any applications executing on the UE, activity of the user, battery level, state of charge, connection (or status) with one or more other RATs or networks, connection (or status) with accompanying or attached devices, congestion, throughput over recent time periods, etc.

In some embodiments, the BS may respond to an indication from the UE of a preferred maximum number of layers. For example, the BS may indicate to the UE that the preferred maximum number of layers will (or will not) be used during one or more time periods.

The UE and/or BS may select a preferred number of layers based on channel conditions, e.g., as determined from one or more measurements. The measurements may occur on any frequency or combination of frequencies, including, for example, licensed and/or unlicensed spectrum. The communication and measurement may last (e.g., periodically, randomly, on-demand, etc.) for any amount of time. For example, measurements may occur over any number of slots, subframes, and/or symbols. These measurements may include any radio link measurement, such as signal-to-noise ratio (SNR), signal-to-interference-plus-noise ratio (SINR), Reference Signal Received Power (RSRP), reference information received quality (RSRQ), Received Signal Strength Indication (RSSI), Channel Quality Indicator (CQI), Rank Indicator (RI), Precoding Matrix Indicator (PMI), and so forth. The UE and/or BS may maintain a history of measurements. The UE/BS may compare the measured values or metrics calculated based on the measured values to one or more thresholds. In such a comparison, the UE/BS may use various parameters, e.g., for hysteresis. The measurements, thresholds, and/or parameters may be configured by the BS (e.g., through the network) and/or by the UE. The UE and/or the BS may report the measurements, comparison results, etc. to each other and/or to the network at any time.

Better channel conditions (e.g., higher measurements of SNR, RSRP, etc., and/or higher channel levels) may be associated with more MIMO layer numbers. For example, a better channel may support more layers. In contrast, according to some embodiments, allocating more resources (e.g., transmission power, bandwidth, etc.) to a smaller number of layers may achieve better performance under poor channel conditions.

According to some embodiments, the UE may dynamically determine an adjusted, dynamic, or conditional maximum number of MIMO layers (604). The UE may determine the adjusted maximum number of MIMO layers based on communication parameters exchanged with the BS. The UE may also determine the number of MIMO layers based on other conditions. For example, the UE may use one or more inactivity timers (e.g., in conjunction with communication parameters) to determine the conditional maximum number of layers that are active at any given time, as explained in more detail below with respect to fig. 9 and 10. The UE may use any combination of communication parameters exchanged with the BS, as well as information regarding other conditions, to determine the adjusted number of communication layers. For example, the UE may consider the combination of channel conditions and any indication received from the BS.

According to some embodiments, the UE may adjust multiple active receiver chains (606). The UE may determine the number of (e.g., adjusted) receiver chains based on the number of (e.g., adjusted) MIMO layers. For example, the UE may adjust the number of active receiver chains to be equal to the number of MIMO layers. In particular, if the number of active receiver chains is greater than the number of MIMO layers, the UE may power down one or more receiver chains, or vice versa.

In some implementations, the UE may further determine which individual receiver chains to power up (e.g., or power down) in order to adjust the active receiver chain number. For example, based on determining that the adjusted number of receiver chains is 2, the UE may refer to a look-up table to determine which 2 receiver chains to power up (and correspondingly which other receiver chains should be powered down).

In some implementations, the UE may determine not to reduce the number of active receiver chains or not to disable all components of the receiver chains based on an amount of time associated with re-powering the receiver chains. For example, if the communication parameters indicate that more MIMO layer numbers may be used in the future, there may not be enough time to power down and power up some or all of the components of the receiver chain (e.g., if the chain or one or more of the chain components are re-powered for as long as the time the chain is used (e.g., within a threshold amount of time)). Thus, the UE may not power down a component that has been recharged for too long a time relative to the amount of time before the component will be used next.

According to some embodiments, the UE may receive data 608. The UE may receive data from the BS or transmitting device using a subset of the active receiver chains (e.g., the receiver chains that are not powered off). The subset of active receiver chains for receiving data may be determined based on the actual number of layers indicated in the DCI. The subset of active receiver chains may include some or all of the active receiver chains. In various possibilities, the data may include payload data and/or additional communication signaling or other control information. Among other possibilities, data may be received in one or more PDSCH messages during one or more time slots or TTIs.

The UE may further adjust the number of active receiver chains for the future time period based on previously received communication parameters, additional communication parameters (e.g., possibly received as part of the data received in 608), and/or other factors (e.g., changing conditions, inactivity timers, etc.). In various possibilities, the timing of further adjusting the number of active receiver chains may depend on the communication parameters received in 602 and/or other parameters received in 608.

In various embodiments, the UE may re-power (e.g., re-power) some or all of the outgoing receiver chains. Such re-powering may occur at times associated with additional downlink data (e.g., based on communication parameters indicating different MIMO layer numbers) and/or may occur periodically. For example, the UE may re-power some or all of the receiver chains after receiving the data and before performing any of various measurements (e.g., Channel State Information (CSI) measurements or maximum support level calculations). Alternatively, or in other cases, the UE may no longer re-power any receiver chains. Further, the UE may de-energize additional receiver chains. Thus, the UE may receive further data with a different (e.g., larger or smaller) subset of active receiver chains for any number of future time periods.

Although the description of the method related to fig. 6 focuses on the UE receiving information, it should be understood that the UE may also transmit data. Such transmission may occur concurrently with, before, or after any of the acts described herein. The UE may use some or all of the same elements (e.g., antennas) for transmission and for reception, or may use different/additional elements. The technique of fig. 6 may be applied to both transmission and reception, or to a combination of transmission and reception functions/chains.

Adjusting the number of receiver chains may require turning the receiver chains (which may include RF components and/or a portion of the component blocks in baseband) on or off. This change may require a certain amount of switching time, which may be referred to as T _ mimo _ layer _ switch. There may be another switching time, denoted T _ BWP _ switch, required to support BWP switching. The BWP switching time, T BWP switch, may vary depending on the subcarrier spacing and UE processing capabilities of the target BWP. When BWP switching involves MIMO layer switching, both switching times may be considered simultaneously. In other words, the UE may consider the time to switch receiver chains and the time to switch BWP when selecting which receiver chain or chains (or components of one or more receiver chains) may be turned off. For example, the UE may consider the longer of the two handover times. For example, if there is no MIMO layer handover during BWP handover, the UE may complete BWP handover during a given time T _ BWP _ switch. However, if BWP handover involves MIMO layer handover (e.g., the MIMO layer of the current BWP is different from the MIMO layer of the target BWP), the UE may consider a longer handover time (e.g., max (T _ MIMO _ layer _ switch, T _ BWP _ switch)) to complete the BWP handover. In other words, if T _ mimo _ layer _ switch is less than or equal to T _ bwp _ switch, then the receiver chain switch time may be considered equal to T _ bwp _ switch.

FIG. 7 and FIG. 8-graphs of Power consumption

Fig. 7 illustrates power consumption of a receiver chain of a UE during a timeslot according to some embodiments. In the illustrated embodiment, 1 codeword may be enabled and a maximum number of 4 receiver (Rx) chains may be required, for example, according to prior art specifications.

At the beginning of the slot (times 702 to 704), the UE may receive the PDCCH using the 4Rx chain. The power consumption shown by the shaded area may be relatively high. The PDCCH may include DCI including an indication of the number of layers to be used for PDSCH transmission later in the time slot. The indication may be included in an antenna port field. The duration of PDCCH reception may vary, but in some embodiments, the duration may be 1-3 OFDM symbols.

PDCCH reception may end and PDSCH reception may begin (time 704). The UE may continue to receive on 4Rx chains and may continue to buffer streams associated with 4 layers. The UE may decode the PDCCH and the DCI. PDSCH reception may continue for the remainder of the time slot (e.g., up to time 710).

The UE may complete decoding of the PDCCH (time 706), completing PDCCH decoding delay. At this point, the UE may determine that, in the illustrated embodiment, the antenna port field indicates that two layers are included in the PDSCH. In other words, the UE may determine that only two layers are actually scheduled. Thus, the UE may begin powering down both receiver chains in order to save power. Removing the receiver chain components may take some time, as indicated by reduced power consumption.

The process of powering down both receiver chains may be completed (time 708), resulting in relatively low power consumption within the remainder of the time slot (e.g., until time 710). The UE may then (at least initially) re-power the powered-off receiver chain for a subsequent time slot or slots.

Fig. 8 is similar to fig. 7. However, fig. 8 illustrates some potential advantages of the technique of fig. 6, in comparison to fig. 7, according to some embodiments. Fig. 8 illustrates power consumption of a receiver chain of a UE during a timeslot according to some embodiments. In the illustrated embodiment, 1 codeword may be enabled and a maximum number of 4 receiver (Rx) chains may be required, for example, according to prior art specifications.

In contrast to fig. 7, based on the previously exchanged communication parameters, the UE may start the time slot shown in fig. 8 with only two Rx chains active (702). In various possibilities, the previously exchanged communication parameters may include an allocation of BWP with a configured (e.g., adjusted, conditioned) maximum of two MIMO layers. In other words, N_{max_L_k}There may be two. Thus, the UE may receive PDCCH using 2 Rx chains (during times 702-704). The power consumption shown by the shaded area may be relatively low, e.g., about half of the corresponding power consumption shown in FIG. 7. The PDCCH may include DCI including an indication of the number of layers to be used for PDSCH transmission later in the time slot. The indication may be included in an antenna port field. The duration of PDCCH reception may vary, but in some embodiments, the duration may be 1-3 OFDM symbols.

PDCCH reception may end and PDSCH reception may begin (time 704). The UE may continue to receive on 2 Rx chains and may continue to buffer flows associated with 2 layers. The UE may decode the PDCCH and the DCI. PDSCH reception may continue for the remainder of the time slot (e.g., up to time 710).

The UE may complete decoding of the PDCCH (time 706), completing PDCCH decoding delay. At this point, the UE may determine that, in the illustrated embodiment, the antenna port field indicates that two layers are included in the PDSCH. In other words, the UE may determine that two layers are actually scheduled. Thus, the UE may determine that no adjustment to the number of active receiver chains is needed for the layer receiving the schedule. Thus, the number of active receiver chains (e.g., 2) and corresponding power consumption may remain (e.g., approximately) constant for the remainder of the time slot (e.g., until time 710).

Although not shown in the illustrated example, it should be understood that in some cases, the number of layers actually scheduled (e.g., the number of layers determined after PDCCH decoding delay) may be less than N_{max_L_k}. In such cases, after the PDCCH decoding delay, the number of active receiver chains may be reduced until the end of the slot. The UE may then re-power the powered-off receiver chain for (at least a portion of) the subsequent one or more time slots.

It should be understood that the relative timing and power consumption shown in fig. 7 and 8 are exemplary only.

FIGS. 9 and 10-Bandwidth portion and inactivity timer

In some embodiments, one or more inactivity timers may be involved during BWP and CDRX operation in RRC connected mode. For example, a DRX inactivity timer (e.g., DRX-inactivity timer) may represent a length of time (e.g., a number of subframes) that the UE must remain active (e.g., continuous) after an uplink or downlink grant. A BWP inactivity timer (e.g., BWP-inactivity timer) may represent an amount of time that the UE must use a first (e.g., larger) BWP after an uplink or downlink grant before transitioning to a second (e.g., smaller) BWP. Note that the two BWPs may have different layer numbers, e.g., the second BWP may be the default BWP and may be configured for fewer layers than the first BWP. These timers may be configured separately (e.g., independent of each other, e.g., either timer may be shorter or longer than the other timer, or the timers may have the same duration). Note that additional or different timers may also be employed, or either of these timers may be used without the other, according to some embodiments. For example, in various possibilities, multiple BWP inactivity timers may be used, e.g., to schedule a series of steps to a smaller BWP.

Fig. 9 and 10 are timing diagrams (e.g., time may run from left to right) illustrating portions of bandwidth and conditional maximum number of MIMO layers relative to an inactivity timer, according to some embodiments.

Fig. 9 illustrates a first case in which the DRX inactivity timer may be longer than the BWP inactivity timer.

A first (e.g., most recent) grant may be made and a DRX inactivity timer and a BWP inactivity timer may be initiated 902. The UE may operate on a first BWP. The first BWP may be BWP2, e.g., the exemplary BWP as discussed above in connection with fig. 6. Thus, N_{max_L_2}May be 2 and the UE may actively receive at layer 2.

The BWP inactivity timer may expire 904. In response to expiration of the BWP inactivity timer, the UE may switch to a second BWP, e.g., BWP1, which may be the default BWP. Thus, N_{max_L_1}May be 1 and the UE may actively receive in a single layer. In other words, layer 1 may continue to be used, but layer 2 may no longer be used.

The DRX inactivity timer may expire 906. Thus, the UE may then begin operating in CDRX mode and repeat the on-duration and off-duration according to the DRX configuration. The UE may continue to operate on BWP1 using layer 1. It is noted that the number of layers to be used may be expressed as min (N)_{max_L_1}，N_{CDRX_L}). In the illustrated embodiment, this expression may be equal to 1, e.g., because N _{max_L_1}1. However, it should be understood that in some embodiments, expiration of DRX inactivity may result in a reduction in the number of active layers, e.g., if N is_{CDRX_L}Less than N_{max_L_K}。

Fig. 10 illustrates a second case in which the DRX inactivity timer may be shorter than the BWP inactivity timer.

A first (e.g., most recent) grant may be made and a DRX inactivity timer may be initiatedAnd a BWP inactivity timer (1002). The UE may operate on a first BWP. The first BWP may be BWP2, e.g., the exemplary BWP as discussed above in connection with fig. 6. Thus, N_{max_L_2}May be 2 and the UE may actively receive at layer 2.

The DRX inactivity timer may expire 1004. In response to expiration of the DRX inactivity timer, the UE may begin operating in CDRX mode with the on duration and the off duration repeated according to the DRX configuration. The UE may continue to operate on BWP2 and may use a single layer (layer 1) during the on-time. Also, the number of layers to be used may be determined as min (N)_{max_L_1，}N_{CDRX_L}). In the case shown in FIG. 10, N_{CDRX_L}May be equal to 1. Thus, N_{CDRX_L}Can be lower than N_{max_L_1}And thus the number of layers can be determined. During DRX on duration, data arrivals may be sparse. Therefore, it may be advantageous to power only the minimum required number of Rx chains (1 in the illustrated embodiment) to save power.

The BWP inactivity timer may expire 1006. Thus, the UE may switch to a second BWP, such as BWP1, which may be the default BWP. Thus, N_{max_L_1}May be 1 and the UE may use a single layer to receive during CDRX on. The UE may continue to operate on BWP 1. Thus, in the illustrated embodiment, the number of layers used may not change, but the size of the BWP may be reduced.

It should be understood that the relative timing and number of layers shown in fig. 9 and 10 are merely exemplary.

FIG. 11 dynamic adjustment of layer number

Fig. 11 is a timing diagram illustrating a technique for dynamically changing the maximum number of layers to be supported. In some embodiments, the number of layers may be adjusted without changing the BWP. The maximum number of layers may be signaled from the BS to the UE using MAC CE or other suitable signaling mechanism (e.g., RRC, DCI, etc.). The maximum number of layers can remain valid for any length of time, typically including more than one time slot. DCI may also be used to indicate the actual number of layers for any single slot. Thus, some timeslots may still use fewer layers than the dynamically adjusted maximum number of layers. However, these techniques may allow the dynamically adjusted maximum number of layers and the number of layers used in at least some of the individual time slots to be more closely tracked, for example, because the maximum value may be adjusted independently of the number of codewords. For example, if one codeword is enabled, one of layer 1, layer 2, layer 3, or layer 4 may be indicated as a dynamically adjusted maximum value. If two codewords are enabled, one of layer 1, layer 2, layer 3, layer 4, layer 5, layer 6, layer 7, or layer 8 may be indicated.

As shown, the channel conditions (e.g., channel level) may vary over time. Other indicators of channel quality or signal strength (e.g., RSRP, SNR, etc.) may be used. At a first time 1102, the BS may transmit a MAC CE to the UE, dynamically setting a maximum number of layers to 2 (e.g., N)_{max_L}2). Such an indication may be transmitted in response to decreasing the channel level, among various possibilities. Such an indication may be transmitted in response to a preference for the maximum number of layers indicated by the UE. After the first indication, the BS may transmit any number of indications to the UE, thereby setting the actual number of layers within a particular time period (e.g., time slot) (1104). For example, the indication may be DCI with an antenna port field. These indications may indicate layer 1 or layer 2 for each respective time slot.

At a later time 1106, the BS may transmit a second indication (e.g., MAC CE) to the UE, dynamically setting the maximum number of layers to 6 (e.g., Nmax _ L ═ 6). In various possibilities, such an indication may be transmitted in response to improving channel conditions. After the second indication, the BS may transmit any number of indications to the UE, thereby setting the actual number of layers within a particular time period (e.g., time slot) (1108). For example, the indication may be DCI with an antenna port field. These indications may indicate layers 1-6 of each respective slot.

It should be appreciated that fig. 11 is merely exemplary, and that any number of indications may be transmitted and other indicators may be used.

In the following, further exemplary embodiments are provided.

In a first set of embodiments, a method for operating a base station may comprise:

establishing, at a base station, a wireless communication link with a user equipment device (UE); determining a first maximum number of multiple-input multiple-output (MIMO) layers for communicating with the UE, wherein the first maximum number of MIMO layers is based on a number of codewords enabled for the UE; transmitting a first communication parameter to the UE, wherein the first communication parameter indicates the first maximum number of MIMO layers; determining an adjusted maximum number of MIMO layers for communicating with the UE; transmitting a second communication parameter to the UE, wherein the second communication parameter indicates the adjusted maximum number of MIMO layers; and transmitting data to the UE using an actual number of MIMO layers, wherein the actual number of MIMO layers is less than or equal to the adjusted maximum number of MIMO layers.

In some embodiments, the second communication parameter may include an indication to the UE to use a first bandwidth portion, wherein the configured maximum number of MIMO layers of the first bandwidth portion is equal to the adjusted maximum number of MIMO layers.

In some embodiments, the first bandwidth portion is a default bandwidth portion, wherein the configured maximum number of MIMO layers of the first bandwidth portion is equal to one.

In some embodiments, the second communication parameter comprises a maximum number of layers to receive during connected mode discontinuous reception (CDRX) of duration.

In some embodiments, the adjusted maximum number of MIMO layers is based, at least in part, on one or more of: a channel condition; or a preference indication received from the UE.

In some embodiments, the second communication parameter comprises a Medium Access Control (MAC) Control Element (CE), wherein the adjusted maximum number of MIMO layers is based at least in part on a channel condition.

In some embodiments, the MAC CE is transmitted to the UE during a first time slot, wherein the adjusted maximum number of MIMO layers applies to one or more second time slots after the first time slot, the method may further comprise: determining a third maximum number of MIMO layers for communicating with the UE, wherein the third maximum number of MIMO layers is determined based at least in part on a change in channel conditions; transmitting a third communication parameter to the UE, wherein the third communication parameter indicates the third maximum number of MIMO layers, wherein the third maximum number of MIMO layers applies to one or more third time slots after the one or more second time slots; and transmitting data to the UE during one or more third time slots using a second actual MIMO layer number, wherein the second actual MIMO layer number is less than or equal to the third maximum MIMO layer number.

In some embodiments, the method may further comprise: transmitting Downlink Control Information (DCI) to the UE, wherein the DCI includes an indication of a number of actual MIMO layers.

In a second set of embodiments, a user equipment device (UE) configured for multiple-input multiple-output (MIMO) wireless communication may comprise: a plurality of receiver chains configured to receive a MIMO communication; a non-transitory computer-readable storage medium; and a processing element coupled to the plurality of receiver chains and the memory medium, wherein the processing element is configured to cause the UE to: establishing communication with a base station; receiving a first communication parameter from the base station; determining a maximum number of MIMO layers based on the first communication parameter; receiving second communication parameters from the base station; determining an adjustment to a maximum number of MIMO layers based on the second communication parameter; and adjusting the plurality of active receiver chains based on the adjustment to the maximum MIMO layer number.

In some embodiments, the UE may be further configured to: receiving Downlink Control Information (DCI) from a base station during a first time slot, wherein the DCI includes an indication of a number of actual MIMO layers from the base station, wherein the number of actual MIMO layers is less than or equal to an adjusted maximum number of MIMO layers; further adjusting the number of active receiver chains based on the actual number of MIMO layers during the first time slot, wherein the further adjusting comprises reducing the number of active receiver chains by de-energizing at least one active receiver chain; and re-powering the at least one active receiver chain for at least a portion of a subsequent time slot.

In some embodiments, the UE may be further configured to: multiple active receiver chains are used to receive data from a base station.

In some embodiments, the UE may be further configured to: indicating, to the base station, a plurality of codewords supported by the UE, wherein the first maximum number of MIMO layers is associated with a number of codewords.

In some embodiments, the UE may be further configured to: indicating a preferred maximum number of MIMO layers to the base station, wherein the adjusted maximum number of MIMO layers is equal to the preferred maximum number of MIMO layers.

In some embodiments, the UE may be further configured to: performing one or more measurements of channel conditions, wherein the preferred maximum number of MIMO layers is based on the one or more measurements of channel conditions.

In some embodiments, an apparatus may comprise: a processing element configured to cause a wireless device to: establishing communication with a base station; receiving at least one communication parameter from the base station; dynamically determining a maximum number of input multiple output (MIMO) layers based on the at least one communication parameter; de-energizing at least a first receiver chain of the plurality of receiver chains based on the maximum number of MIMO layers, wherein a first subset of the plurality of receiver chains remains powered; and receiving data from the base station using the first subset of the plurality of receiver chains.

In some embodiments, the maximum number of MIMO layers is further based on at least one inactivity timer.

In some implementations, the at least one inactivity timer may include: a Discontinuous Reception (DRX) inactivity timer; and a bandwidth part (BWP) inactivity timer.

In some embodiments, the at least one communication parameter comprises: a maximum number of layers for a first BWP; and a maximum number of layers for the second BWP.

In some embodiments, the at least one communication parameter comprises a maximum number of layers for connected mode discontinuous reception (CDRX) for a duration.

In some embodiments, the processing element may be further configured to cause the wireless device to: receiving second communication parameters from the base station, wherein the second communication parameters are received via a Media Access Control (MAC) Control Element (CE); dynamically determining a second maximum number of MIMO layers based on the second communication parameter; de-energizing at least one other receiver chain of the plurality of receiver chains based on a second maximum number of MIMO layers; and receiving second data from the base station using at least a second subset of the plurality of receiver chains, wherein the second subset includes fewer receiver chains than the first subset.

Embodiments of the present disclosure may be implemented in any of various forms. For example, some embodiments may be implemented as a computer-implemented method, a computer-readable memory medium, or a computer system. Other embodiments may be implemented using one or more custom designed hardware devices, such as ASICs. Other embodiments may be implemented using one or more programmable hardware elements, such as FPGAs.

In some embodiments, a non-transitory computer-readable memory medium may be configured such that it stores program instructions and/or data, wherein the program instructions, if executed by a computer system, cause the computer system to perform a method, e.g., any of the method embodiments described herein, or any combination of the method embodiments described herein, or any subset of any of the method embodiments described herein, or any combination of such subsets.

In some embodiments, a device (e.g., UE 106) may be configured to include a processor (or a set of processors) and a memory medium, wherein the memory medium stores program instructions, wherein the processor is configured to read and execute the program instructions from the memory medium, wherein the program instructions are executable to implement any of the various method embodiments described herein (or any combination of the method embodiments described herein, or any subset of any of the method embodiments described herein, or any combination of such subsets). The apparatus may be embodied in any of a variety of forms.

It is well known that the use of personally identifiable information should comply with privacy policies and practices that are recognized as meeting or exceeding industry or government requirements for maintaining user privacy. In particular, personally identifiable information data should be managed and processed to minimize the risk of inadvertent or unauthorized access or use, and the nature of authorized use should be explicitly stated to the user.

Although the above embodiments have been described in considerable detail, numerous variations and modifications will become apparent to those skilled in the art once the above disclosure is fully appreciated. It is intended that the following claims be interpreted to embrace all such variations and modifications.

Claims

1. A method for operating a base station, the method comprising:

at the base station:

establishing a wireless communication link with a user equipment device (UE);

determining a first maximum number of multiple-input multiple-output (MIMO) layers for communicating with the UE, wherein the first maximum number of MIMO layers is based on a number of codewords enabled for the UE;

transmitting a first communication parameter to the UE, wherein the first communication parameter indicates the first maximum number of MIMO layers;

determining an adjusted maximum number of MIMO layers for communicating with the UE;

transmitting a second communication parameter to the UE, wherein the second communication parameter indicates the adjusted maximum number of MIMO layers;

transmitting downlink control information to the UE, wherein the downlink control information indicates an actual MIMO layer number that is less than or equal to the adjusted maximum MIMO layer number; and

transmitting data to the UE using the actual MIMO layer number.

2. The method of claim 1, wherein the second communication parameter comprises an indication to the UE to use a first bandwidth part, wherein a configured maximum number of MIMO layers of the first bandwidth part is equal to the adjusted maximum number of MIMO layers.

3. The method of claim 2, wherein the first bandwidth portion is a default bandwidth portion, wherein the configured maximum number of MIMO layers of the first bandwidth portion is equal to one.

4. The method of claim 1, wherein the second communication parameter comprises a maximum number of layers to receive during connected mode discontinuous reception (CDRX) of duration.

5. The method of claim 1, wherein the adjusted maximum number of MIMO layers is based at least in part on a preference indication received from the UE.

6. The method of claim 1, wherein the second communication parameter comprises a Medium Access Control (MAC) Control Element (CE), wherein the adjusted maximum number of MIMO layers is based at least in part on a channel condition.

7. The method of claim 6, wherein the MAC CE is transmitted to the UE during a first time slot, wherein the adjusted maximum number of MIMO layers applies to one or more second time slots after the first time slot,

the method further comprises:

determining a third maximum number of MIMO layers for communicating with the UE, wherein the third maximum number of MIMO layers is determined based at least in part on a change in channel conditions;

transmitting a third communication parameter to the UE, wherein the third communication parameter indicates the third maximum number of MIMO layers, wherein the third maximum number of MIMO layers applies to one or more third time slots after the one or more second time slots;

transmitting second downlink control information indicating a second actual number of MIMO layers to the UE, the second actual number of MIMO layers being less than or equal to the third maximum number of MIMO layers; and

transmitting data to the UE during the one or more third time slots using the second actual MIMO layer number.

8. A user equipment device (UE) configured for multiple-input multiple-output (MIMO) wireless communication, the UE comprising:

a plurality of receiver chains configured to receive a MIMO communication; and

a processor coupled to the plurality of receiver chains and configured to cause the UE to:

establishing communication with a base station;

receiving a first communication parameter from the base station;

determining a maximum number of MIMO layers based on the first communication parameter;

receiving second communication parameters from the base station;

determining an adjusted maximum number of MIMO layers based on the second communication parameter;

adjusting the number of active receiver chains based on the adjusted maximum number of MIMO layers;

receiving Downlink Control Information (DCI) from the base station, the DCI indicating an actual MIMO layer number that is equal to or less than the adjusted maximum MIMO layer number; and

receiving downlink data from the base station using at least one of the active receiver chains corresponding to the actual MIMO layer number.

9. The UE of claim 8, wherein the DCI is received from the base station during a first time slot, wherein the processor is further configured to cause the UE to:

de-electrifying at least one active receiver chain during the first time slot, wherein the downlink data is received during the first time slot and after the de-electrifying; and

re-powering the at least one active receiver chain for at least a portion of a subsequent time slot.

10. The UE of claim 8, further configured to:

indicating to the base station a number of codewords supported by the UE, wherein the first maximum number of MIMO layers is associated with the number of codewords.

11. The UE of claim 10, further configured to:

indicating a preferred maximum number of MIMO layers to the base station, wherein the adjusted maximum number of MIMO layers is equal to the preferred maximum number of MIMO layers.

12. The UE of claim 11, further configured to:

performing one or more measurements of channel conditions, wherein the preferred maximum number of MIMO layers is based on the one or more measurements of channel conditions.

13. The UE of claim 8, wherein the number of MIMO layers adjusted is determined based on both:

a Discontinuous Reception (DRX) inactivity timer; and

a bandwidth part (BWP) inactivity timer.

14. An apparatus, comprising:

a processor configured to cause a wireless device to:

establishing communication with a base station;

receiving a first communication parameter from the base station;

determining a static maximum number of multiple-input multiple-output (MIMO) layers based on the first communication parameter;

receiving second communication parameters from the base station;

determining a dynamic maximum number of MIMO layers based on the second communication parameter;

de-energizing at least a first receiver chain of a plurality of receiver chains based on the dynamic maximum number of MIMO layers, wherein a first subset of the plurality of receiver chains remains powered; and

receiving data from the base station using the first subset of the plurality of receiver chains.

15. The apparatus of claim 14, wherein the dynamic maximum number of MIMO layers is further based on at least one inactivity timer.

16. The apparatus of claim 15, wherein the at least one inactivity timer comprises a bandwidth part (BWP) inactivity timer and the second communication parameter comprises a maximum number of layers for a first BWP.

17. The apparatus of claim 16, wherein the second communication parameters further comprise a maximum number of layers for a second BWP.

18. The apparatus of claim 17, wherein the at least one inactivity timer further comprises a Discontinuous Reception (DRX) inactivity timer, wherein the second communication parameters further comprise a maximum number of layers of connected mode discontinuous reception (CDRX) over an duration.

19. The apparatus of claim 14, wherein the first and second electrodes are disposed on opposite sides of the substrate,

wherein the first communication parameter comprises maxNrofCodeWordsSchedulByDCI indicating one codeword,

wherein the second communication parameter comprises a Media Access Control (MAC) Control Element (CE) indicating that the dynamic maximum MIMO layer number is less than 4.

20. The apparatus of claim 14, wherein the processing element is further configured to cause the wireless device to:

receiving further communication parameters from the base station, wherein the further communication parameters are received via a Media Access Control (MAC) Control Element (CE);

adjusting the dynamic maximum number of MIMO layers based on the further communication parameter;

de-energizing at least one other receiver chain of the plurality of receiver chains based on the adjustment to the dynamic maximum MIMO layer number; and

receiving second data from the base station using at least a second subset of the plurality of receiver chains, wherein the second subset includes fewer receiver chains than the first subset.